How All Those Forever Chemicals End Up on Your Plate

After teeny ocean organisms pick up lingering forever chemicals swirling in water, these man-made substances travel up the food chain—from, say, krill, to anchovies, to the tuna that we place in our grocery carts.

These chemicals, also known as per- and polyfluoroalkyl substances or PFAS, are used in more than 200 categories of manufactured products. They’re valued for their water-repelling abilities and heat resistance—but they also stick around in soil, air and water across the globe and don’t degrade over time due to their super strong chemical bonds. Scientists have documented PFAS in the environment in regions as remote as Antarctica.

Now, scientists have found that concentrations of some PFAS double on average each time the substances creep up one rung of the food chain, findings reported in Nature Communications. These increases seem to occur when animals absorb the compounds quicker than they can metabolize or expel them.

An international team of scientists analyzed how PFAS moved across more than 100 food webs spanning land and water. Gathering data from 64 studies, they conducted the first meta-analysis of data on PFAS accumulation across food chains around the world. The researchers hoped to clear up inconsistencies in past research, which has pointed to both minor amounts of PFAS accumulating in some food webs and massive build-up in others.